Today's desktop and laptop computers may include wireless network interface cards (WNIC) to function as network nodes, or “stations,” in wireless networks. Generally, these computers may be in either an “awake” power state or a “sleep” power state. In the awake power state, the WNIC and the remainder of the computer (host system) are both powered up and in an operational mode. In a sleep power state, power to the host system is shut off with state information suspended to disk/RAM, and the WNIC is powered off. Compared with an awake state, sleep states can significantly reduce power consumption; however, the computer is not able to receive wireless network traffic when in a sleep state since the WNIC is powered off.
Some network nodes in wired networks include a “wake-on-LAN” mechanism to enable the nodes to switch to an awake state from a sleep state when receiving a known packet pattern over a wired network. As “all wireless” enterprise campuses evolve, the enterprise may wish to implement the wake-on-LAN functionality in wireless networks. Unfortunately, known wake-on-LAN mechanisms are problematic in wireless networks for various reasons. For example, a WNIC may not be able to decrypt packets because the keys may have expired since keys stored in the WNIC cannot be refreshed while the system is sleeping. Also for example, an association between a station and access point may be lost while the WNIC is sleeping.